****************
Kinetic friction
****************

====
Name
====

Define the name of the link property. 

============
Physics type
============

Shows if the link property is mechanical or thermal.

=============
Property type
=============

Shows the link property type.

=========================
Friction force and torque
=========================

Define the direction of the friction force. The friction force 
should be applied in opposite direction of the movement.

=================
Build-up velocity
=================

Define the velocity at which 96% of the friction force is built up. 

==============
Friction model
==============

The friction force is calculated according to the following equation:

.. math::  f = f_v * tanh(2/v_b*v)

===========  =======================
Variable     Description
===========  =======================
:math:`f`    friction reaction force
:math:`f_v`  direction of friction
:math:`v_b`  build-up velocity
:math:`v`    link velocity
===========  =======================

=========
Linearize
=========

The non-linear effect of the kinetic friction can be omitted in the analyses by ticking the 
linearize link properties box. Check the user help for analyses for further information on linearization.